Percentage of observations where the VFR minimums for ceiling and visibility are met: visibility of 5 mi or more and a ceiling of 3,000 ft or more. Only observations between sunrise and sunset are taken into account.
Marginal VFR conditions (%)
Month
Average
2024
2023
2022
2021
2020
January
81.3
69
84
85
79
75
February
81.7
71
80
82
80
87
March
76.7
63
71
74
80
93
April
78.3
67
76
63
82
May
81.7
86
80
79
81
June
88.5
99
94
90
88
July
84.2
67
61
93
83
August
80.8
100
86
83
74
September
80.9
81
89
80
72
October
76.2
74
62
75
80
November
79.4
71
80
77
89
December
71.6
47
66
78
79
Average
78.8
67.1
77.8
79.0
79.0
81.7
Marginal VFR conditions or better during daylight period
Percentage of observations where the MVFR minimums for ceiling and visibility are met: visibility of 3⅛ mi or more and a ceiling of 1,000 ft or more. Only observations between sunrise and sunset are taken into account.
Maximum temperatures (°C)
Month
Average
2024
2023
2022
2021
2020
January
-22.6
-20
-23
-26
-12
-22
February
-24.5
-22
-29
-26
-18
-24
March
-15.1
-13
-13
-16
-17
-16
April
-8.3
-7
-8
-4
-8
May
0.3
1
0
1
-1
June
7.7
10
11
6
7
July
13.7
13
12
13
16
August
12.7
19
13
12
15
September
7.0
6
11
7
6
October
1.4
3
2
4
0
November
-8.8
-5
-7
-5
-8
December
-13.2
-10
-10
-12
-14
Average
-7.8
-18.1
-6.2
-5.2
-2.1
-5.9
Average highest temperature per day
The maximum temperature is typically observed some hours after noon.